Zebra mussels (Dreissena polymorpha) were translocated in cages to 56 water bodies in Flanders (Belgium) during summer 2001. After six weeks, concentrations of polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), p,p'-DDE, and trace metals were measured in the transplanted mussels. It was investigated whether total dissolved water and sediment pollutant levels or bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) were predictive for mussel tissue levels. The sample sites covered a broad range both in terms of the type and concentration of the pollutants, and this was reflected in large differences in tissue concentrations of all pollutants among the sites. The highest pollutant levels in mussels were among the highest reported in the literature. For Cd and Zn levels up to 33 and 1994 microg/g dry wt. respectively were found. The lowest levels were comparable to those from uncontaminated sites in Europe and the U.S. For Cd and Zn respectively 51 and 75% of the variation in tissue levels was described. For both metals, dissolved and particulate metal contributed to the variation in accumulation. For other pollutants, relationships between tissue concentration and water or sediment concentration were weak or nonsignificant. Then the measured environmental factors (dissolved calcium, pH, oxygen, organic carbon and clay content in the sediment) were taken into account applying multiple regression analysis, and no increase in the described variation of pollutant accumulation was observed. The BAF and BSAF for all pollutants varied up to 1000-fold even after TOC-normalization. Clear negative relationships were found between BAFs/ BSAFs and environmental levels. However, even at constant environmental concentrations a 10- to 100-fold variation in BAFs/BSAFs was observed. This study illustrated the need for biological monitoring since neither environmental

Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis[(trifluoromethyl)sulfonyl]imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100−500 for pertechnetate), significant electrical conductivity (>100 μS/cm), and a wide (∼4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions.

Since the first North Sea Conference (1984, Bremen), all countries bordering the North Sea made commitments to reduce discharge of hazardous substances into the North Sea. From Belgium and The Netherlands, large reductions (upto 90%) in heavy metal emissions from land-based sources have been reported between 1985 and 2000. Recently, some studies in the Western Scheldt estuary (WS) have shown that total metal concentration in the water, sediments and suspended particles have decreased compared to levels in the 70s. However, data on aquatic organisms is still very limited and it is therefore difficult to confirm whether the reductions in pollution input and generally improving water quality in the WS have a corresponding impact on the levels of heavy metals in aquatic organisms. The current study measured metal concentrations in the soft tissues of mussels, Mytilus edulis (known to be good indicators of environmental metal pollution) during the period 1996-2002. Spatial (salinity and pollution gradients), temporal and seasonal variations were also studied. Results showed a down-stream decreasing trend for the metals studied (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) during all sampling campaigns. There was also a significant seasonal effect on tissue metal concentrations, with a peak observed around spring in both WS and the nearby less polluted Eastern Scheldt (ES). On temporal trends, a clear drop of metals in mussels was observed in the early 80s coinciding with the start of the efforts to reduce chemical pollution input into the North Sea. Since those early reductions, metal concentrations in mussels generally remained unchanged upto mid 90s. However, in recent times metal concentration in mussels have increased significantly, for example Cd in 2002 was almost 10 times the values in 1983 and similar to levels seen during the peak in the 70s. Other metals also increased in the 90s also reaching levels seen in the 70s. As there is no indication of recent increase in metal input into the estuary, we suggest that increased metal concentrations observed in mussels in recent years especially in the upper estuary are most likely a result of changes in physical and chemical speciation and metal bioavailability. Such changes may be caused by changes in some water quality parameters in the estuary (i.e. increased dissolved oxygen, concentration of organic matter), resulting in conditions that favour releases of sediment-bound metals into the water column. The relationship between metal content and season showed very similar annual profiles in the polluted WS and less polluted ES. Thus, seasonal variations in metal concentrations appear to be largely controlled by biological processes, while total body burdens are dependent on environmental levels and bioavailability.

Organic solute partitioning between a hydrophobic deep eutectic solvent and water is directly related to the corresponding Pow values.

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